As grim as the Working Group 2 report on impacts is, it explicitly has very little to say about the catastrophic impacts and vulnerability in the business as usual case where the Earth warms 4°C to 5°C [7°F-9°F] — and it has nothing to say about even higher warming, which the latest science suggests we are headed toward.

It warns that we are doing a bad job of dealing with the climate change we’ve experienced to date: “Impacts from recent climate-related extremes, such as heat waves, droughts, floods, cyclones, and wildfires, reveal significant vulnerability and exposure of some ecosystems and many human systems to current climate variability.”

It warns of the dreaded RFCs (“reasons for concern” — I’m not making this acronym up), such as “breakdown of food systems linked to warming, drought, flooding, and precipitation variability and extremes.” You might call them RFAs (“reasons for alarm” or “reasons for action”). Indeed, in recent years, “several periods of rapid food and cereal price increases following climate extremes in key producing regions indicate a sensitivity of current markets to climate extremes among other factors.” So warming-driven drought and extreme weather have already begun to reduce food security. Now imagine adding another 2 billion people to feed while we are experiencing five times as much warming this century as we did last century!

No surprise, then, that climate change will “prolong existing, and create new, poverty traps, the latter particularly in urban areas and emerging hotspots of hunger.” And it will “increase risks of violent conflicts in the form of civil war and inter-group violence” — though for some reason that doesn’t make the list of RFCs.

In short, “We’re all sitting ducks,” as IPCC author and Princeton Prof. Michael Oppenheimer put it to the AP. AN OVERLY CAUTIOUS REPORT

As grim as the Working Group 2 report on impacts is, it explicitly has very little to say about the catastrophic impacts and vulnerability in the business as usual case where the Earth warms 4°C to 5°C [7°F-9°F] — and it has nothing to say about even higher warming, which the latest science suggests we are headed toward.

The report states:

“Relatively few studies have considered impacts on cropping systems for scenarios where global mean temperatures increase by 4°C [7°F] or more.

“… few quantitative estimates [of global annual economic losses] have been completed for additional warming around 3°C [5.4°F] or above.”………

THE HIGH COST OF INACTION

The IPCC’s discussion of economic costs is equally muddled:

“… the incomplete estimates of global annual economic losses for additional temperature increases of ~2°C are between 0.2 and 2.0% of income. Losses are more likely than not to be greater, rather than smaller, than this range…. Losses accelerate with greater warming, but few quantitative estimates have been completed for additional warming around 3°C or above.”

It would have been nice if the IPCC had mentioned at this point that keeping additional temperature increases to ~2°C requires very aggressive efforts to slash carbon pollution starting now. As it is, the deniers, confusionists, and easily confused can (incorrectly) assert that this first sentence means global economic losses from climate change will be low. Again, that’s only if we act now.

As Climate Science Watch noted Saturday, “Other estimates suggest the high impacts on global GDP with warming of 4ºC (For example the Stern Review found impacts of 5-20% of global GDP).”

The costs of even higher warming, which, again, would be nothing more than business as usual, rise exponentially. Indeed, we’ve known for years that traditional climate cost-benefit analyses are “unusually misleading” — as Harvard economist Martin Weitzman warned colleagues, “we may be deluding ourselves and others.” Again, that’s because the IPCC is basically a best case analysis — while it largely ignores the business-as-usual case and completely ignores the worst case……http://thinkprogress.org/climate/2014/03/30/3420723/climate-breakdown-of-food-systems/